Introduction
Perhaps one of the biggest societal issues of our era is when does an embryo have the same rights as a baby. Abortion issues are still being challenged and now we come to the new era of stem cells. When is it appropriate to use stem cells and when is it not? Is it ethical to abort a fetus at 24 weeks? If so, is it is ethical to use a cell, that does not have the potential of becoming a fetus for the purpose of curing a debilitating disease or perhaps giving a person afflicted with one of these incurable diseases a better quality of life? How can we make moral decisions without all of the facts?
In order to help us make the most rational and sound decisions we need to know all of the facts. What exactly are stem cells and where do they come from? Do you have to kill a fetus to get them? What diseases could be helped by the use of stem cells? Once we have all of the facts, perhaps we will be better equipped to answer some of these questions. Then we can decide whether or not we accept the current U.S. Legislation on Embryonic Stem Cells.
What are Cells and Their Functions?
Cells are the basic building blocks of the human body. They are the smallest units of life. Each cell holds a nucleus with DNA that holds all of our genetic material. The cell also consists of small structures called organelles; these organelles are like little factories. They process nutrients and produce necessary energy. These individual cells form tissues and tissues form organs. All of the organs in the body such as the heart and lungs organs form organ systems, such as the respiratory system. These organ systems work together to form the organism. The start of pregnancy starts from an egg and a sperm. Under the right conditions, these two cells will join and divide forming an embryo, a fetus, and then a baby.
What is "Cell Therapy" and How Does "Cell Therapy" Work?
This therapy is similar to the process of organ transplant, only the treatment consists of the transplantation of cells rather than organs. The implanted cells would take over the diseased cells and a person could be cured from a disease. Research is still being done to make this happen and is very promising.
What are Stem Cells?
Stem cells are the "master cells." They have the ability to divide for indefinite periods in culture and have the ability to transform into specialized cells. It all begins with a sperm and an egg. A fertilized egg creates a single cell that has the potential to form an entire organism.
(http://www.nih.gov/news/stemcell/primer.htm).
Totipotent
The fertilized egg is totipotent, meaning that its potential is total. In the first few hours, after fertilization takes place, the fertilized egg will divide into two identical cells. These identical cells are the totipotent cells. If either one of these cells, is implanted into a woman's uterus, it has the potential to develop into a fetus. Identical twins develop when two totipotent cells separate and develop into two individuals.
(http://www.nih.gov/news/stemcell/primer.htm)
Blastocyst
Approximately four days after fertilization and after several cycles of cell division, the totipotent cells will form a hollow sphere of cells, called a blastocyst. The blastocyst has an outer layer of cells and inside the hollow sphere, there is a cluster of cells called the inner cell mass.
(http://www.nih.gov/news/stemcell/primer.htm).
Pluripotent AKA Embryonic Stem Cells
The inner cell mass of the blastocyst are the pluripotent or what you often hear "embryonic stem cells".
These cells are highly versatile and can specialize into any cell type except the cells of the placenta. (http://www.stemcellresearchfoundation.org/About/FAQ.htm#1). The outer layer of cells form the placenta and other supporting tissues necessary for fetal development. The inner cell mass cells will go on to form essentially all of the tissues of the human body. Although the inner cell mass cells can form basically every type of cell found in the human body, they cannot form an organism because they do not have the ability to form the placenta and supporting tissues necessary for development in the human uterus. Because pluripotent cells do not have the potential to develop into a fetus there potential is not total and unlike the totipotent cells, if placed into a woman's uterus, it does not have the ability to develop into a fetus. (http://www.nih.gov/news/stemcell/primer.htm). Pluripotent cells are the cells of interest, because, it is believed that someday they could be used to replace diseased cells and tissues in a broad range of diseases, including Alzheimer's, Parkinson's, juvenile diabetes, heart disease and cancer, to name just a few." (http://www.stemcellresearchfoundation.org/About/FAQ.htm#1). Pluripotent cell are especially important in finding possible cures for neurological diseases that affect the brain, as the brain does not have the capabilities of regenerating itself. This is why, quite frequently, you will hear in the news about research on embryonic stem cells. These are the cells they are referring about.
Multipotent
The pluripotent cells continue to divide and the cells will become multipotent. Multipotent, meaning they can form several other cell types, but these types are limited in number.
(http://www.stemcellresearchfoundation.org/About/FAQ.htm#1). Types of multipotent cells include blood stem cells, which can go on to form red blood cells, white blood cells and platelets; Multipotent cells can also form skin stem cells. The multipotent blood cells are limited because they cannot develop into brain cells. Blood stem cells reside in the bone marrow of every child and adult, and can be found in small numbers circulating in the blood stream. "Blood stem cells perform the critical role of continually replenishing our supply of blood cells throughout life. A person cannot survive without blood stem cells." (http://www.stemcellresearchfoundation.org/About/FAQ.htm#1).How are Pluripotent Stem Cells Derived?
At present, human pluripotent cell lines have been developed from two sources with methods developed previously in work with animal models. Although the cells developed were derived from different sources, they appear to be very similar. (
http://www.nih.gov/news/stemcell/primer.htm).(1) "
Pluripotent stem cells are isolated directly from the inner cell mass of human embryos at the blastocyst stage. The embryos are received from IVF (In Vitro Fertilization) clinics. These embryos were in excess of the clinical need for infertility treatment. The embryos were made for purposes of reproduction, not research. Informed consent is obtained from the donor couples. The inner cell mass is isolated and cultured producing a pluripotent stem cell line." (http://www.nih.gov/news/stemcell/primer.htm).(2) The second is isolating pluripotent stem cells from fetal tissue obtained from terminated pregnancies. Informed consent was obtained from the donors after they had independently made the decision to terminate their pregnancy Cells are taken from the region of the fetus that was destined to develop into the testes or the ovaries. (
http://www.nih.gov/news/stemcell/primer.htm).Adult Stem Cells vs. Embryonic Aren't They the Same?
"Many people have asked why embryonic stem cells are needed, when adult bodies also produce stem cells. The answer is that they are not the same. While there is still much to be learned about cell therapy, scientists are fairly certain that pluripotent stem cells do not exist in the adult body. So far, only very early embryos (within the first two weeks after the fertilization of an egg) contain these master cells. And although adult bodies do have some multipotent stem cells, those cells will have experienced some DNA damage due to the natural process of aging. It is this slowly accumulating damage to our cells' DNA that leads to many cancers in adulthood, and means that transplants of adult cells could raise the risk of cancer. And adult cells will definitely not have the same life span of embryonic cells, which could lay the foundation for other diseases later on. While it is possible that scientists may someday be able to accomplish the same goals with adult cells as with embryonic ones, that day could be many years in the future."
(http://www.stemcellresearchfoundation.org/About/FAQ.htm#1).
2-"Research on human adult stem cells suggests that these multipotent cells have great potential for use in both research and in the development of cell therapies. The use of adult stem cells for such cell therapies would certainly reduce or even avoid the practice of using stem cells that were derived from human embryos or human fetal tissues, sources that trouble many people on ethical grounds." (
http://www.nih.gov/news/stemcell/primer.htm).3-"While adult stem cells hold real promise, there are some significant limitations to what we may or may not be able to accomplish with them. First of all, stem cells from adults have not been isolated for all tissues of the body. Although many different kinds of multipotent stem cells have been identified, adult stem cells for all cell and tissue types have not yet been found in the adult human. For example, we have not located adult cardiac stem cells or adult pancreatic islet stem cells in humans." (
http://www.nih.gov/news/stemcell/primer.htm).4-"Adult stem cells are often present in only minute quantities, are difficult to isolate and purify, and their numbers may decrease with age. For example, brain cells from adults that may be neuronal stem cells have only been obtained by removing a portion of the brain of epileptics." (
http://www.nih.gov/news/stemcell/primer.htm). I don’t think this is a procedure that is going to happen under normal circumstances.5-"Any attempt to use stem cells from a patient's own body for treatment would require that stem cells would first have to be isolated from the patient and then grown in culture in sufficient numbers to obtain adequate quantities for treatment. For some acute disorders, there may not be enough time to grow enough cells to use for treatment." (
http://www.nih.gov/news/stemcell/primer.htm).6-In other disorders, caused by a genetic defect, the genetic error would likely be present in the patient's stem cells. Adult stem cells may contain more DNA abnormalities, caused by exposure to environmental toxins and by errors made in DNA replication during the course of a lifetime. (
http://www.nih.gov/news/stemcell/primer.htm).
What is Cord Blood and What Does It Have to do With Stem Cells?
1-Cord blood is the blood that remains in the umbilical cord after your baby is born. It is rich in stem cells like bone marrow. It is the building blocks of the blood and immune system and potentially the nervous system. (http://www.viacord.com)
2-It provides a readily available source of stem cells for transplantation in many situations where bone marrow is considered.
(http://www.viacord.com)3-The opportunity to preserve a baby’s cord blood is only available at the time of birth. The collection process, done after a baby is born. It is easy, painless, and non-invasive. (http://www.viacord.com) When the baby is delivered, the umbilical cord is clamped and cut. The baby is then, removed from the birthing area prior to commencing the collection of umbilical cord blood. Next, before the placenta is delivered, the obstetrician or midwife will clean a 4- to 8-inch area of umbilical cord with antiseptic solution and insert the blood bag needle into the umbilical cord vein. The blood flows into the bag by gravity, until it stops, after which the collection is complete. The blood bag is clamped, sealed and labeled. The collection typically takes 2-4 minutes. Two tubes of maternal blood are also drawn. (
http://www.viacord.com)Why Are Pluripotent Stem Cells Important in Advances in Health Care?
There are several important reasons why the isolation of human pluripotent stem cells is important to science and to advances in health care.
1-Stem cells could help us to understand the complex events that occur during human development. (
http://www.nih.gov/news/stemcell/primer.htm).2-Human pluripotent stem cell research could also dramatically change the way we develop drugs and test them for safety. For example, new medications could be initially tested using human cell lines
". (http://www.nih.gov/news/stemcell/primer.htm).3-"Perhaps the most far-reaching potential application of human pluripotent stem cells is the generation of cells and tissue that could be used for "cell therapies." Many diseases and disorders result from disruption of cellular function or destruction of tissues of the body. Today, donated organs and tissues are often used to replace ailing or destroyed tissue. Unfortunately, the number of people suffering from these disorders far outstrips the number of organs available for transplantation. Pluripotent stem cells, stimulated to develop into specialized cells, offer the possibility of a renewable source of replacement cells and tissue to treat a infinite number of diseases, conditions, and disabilities." (
http://www.nih.gov/news/stemcell/primer.htm).What Diseases Could Be Treated With "Cell Therapies"?
The possibilities of treating diseases with cell therapy are endless. The potential of regenerating neurons in the brain would be evolutionary. It could be used for diseases such as Alzheimer’s, Parkinson’s, Leukodystrophies, Lou Gherig’s, and Multiple Sclerosis. It could also be used in victims of spinal cord injuries and strokes.
How Are Cell Therapies Being Used Today?
Most of the work in this field has been experimental.
Most scientists think cell therapy has promise and it is only a matter of time before its use becomes standard. While many of the uses of cell therapy sound advanced, there are a few forms of this technique that have already been in use:
Challenges of Stem Cell Therapy.
1- Difficulty of identifying stem cells in tissue cultures (
http://www.nih.gov/news/stemcell/primer.htm).2-Finding the right way to implement cells into the body. (
http://www.nih.gov/news/stemcell/primer.htm).3- Once the cells have been implanted they must be integrated into the patient's own tissues and organs and "learn" to function in harmony with the body's natural cells.
4- Just as in organ transplants, the body's immune system would recognize the transplanted cells as "foreign," and set off an immune reaction. This reaction could cause the transplanted cells to fail and possibly endanger the patient. Cell recipients would have to take drugs to temporarily suppress their immune systems. The immune suppressing drugs could also be dangerous to the patient. (
http://www.nih.gov/news/stemcell/primer.htm).5-"Another concern is the possible risk of cancer. Cancer results when cells lose their internal "brakes" and keep dividing when further multiplication is not needed. (
http://www.nih.gov/news/stemcell/primer.htm).What is the Current Legislation on Embryonic Stem Cells?
"
On August 9, 2001, at 9:00 p.m. EDT, the President announced his decision to allow Federal funds to be used for research on existing human embryonic stem cell lines as long as prior to his announcement (1) the derivation process (which commences with the removal of the inner cell mass from the blastocyst) had already been initiated and (2) the embryo from which the stem cell line was derived no longer had the possibility of development as a human being." (http://escr.nih.gov/).In addition, the following criteria that must be met:
The stem cells must have been derived from an embryo that was created for reproductive purposes.
The embryo was no longer needed for these purposes.
Informed consent must have been obtained for the donation of the embryo.
No financial inducements were provided for donation of the embryo. (http://escr.nih.gov/).
This legislation is limited in that there are only 78 stem cell lines worldwide that fit into this criteria, with only 5 labs in the U.S. holding 27 stem cell lines
. (http://escr.nih.gov/).Facts about Neurological Disorders That May One Day Be Helped By Cell Therapy.
There are no known cures.
There is only symptomatic treatment and supportive services such as physical therapy, special education and caregiving. (http://www.cnsfoundation.org).
Every 53 seconds, someone in America has a stroke, which is equivalent to about 600,000 victims a year.
In the United States, it is the number No. 3 killer and is a leading cause on severe, long-term disability. (http://www.strokeassociation.org)
There are approximately 15 million children in the United States, 0-19 years of age with have neurological conditions that severely limit their quality of life and lifespan.
(http://www.cnsfoundation.org). Special education costs approximately 36 billion dollars annually. (http://www.cnsfoundation.org)Autism affects an estimated 10 to 20 of every 10,000 people. It is about four times more prevalent in males than females
. (http://www.ninds.nih.gov).Approximately, 3 million people in the U.S. are affected with epilepsy. About 30% diagnosed with epilepsy suffer from seizures that cannot be controlled by medication.
(http://www.CUREepilepsy.org).Multiple sclerosis (MS) attacks the white matter of the central nervous system. Currently there is an estimated 2.5 million people affected worldwide. It is estimated that 250, 000 to 350, 000 people are affected in the United States.
It manifests itself mainly in adults 20 to 50 years of age. The exact cause of MS is unknown; it is suspected that a viral infection could be the cause. Its symptoms include any combination of spastic paraparesis, unsteady gait, diplopia, and incontinence. (http://www.myelin.org).250,000 Americans have a spinal cord injury. Approximately 11,000 new injuries occur each year. 82% are male. 56% of injuries occur between the ages of 16 and 30. The average age of spinal cord injured person is 31. Only 52% of SCI individuals are covered by private health insurance at time of injury. Paralysis caused by spinal cord injury costs an estimated $400 billion a year in medical care and other costs.
52% of spinal cord injured individuals are considered paraplegic and 47% quadriplegic. (http://www.paralysis.org).Scientists think that up to 4 million Americans suffer from Alzheimer’s disease (AD). Typically the disease begins after age 60, and risk goes up with age. There are younger people who suffer from AD, but it is less common. About 3 percent of men and women ages 65 to 74 have AD, AD is not a normal part of aging. (http://www.alzheimers.org).
It is estimated that up to 1.5 million Americans are affected with Parkinson’s disease (PD).
15% of patients are diagnosed before age 50. Parkinson's disease affects one of every 100 persons over the age of 60. (http://www.parkinson.org).
Conclusion
Like abortion, the controversy of using stem cells for research and or cell therapy, will be a long debate. The laws for abortion starting from Roe v. Wade have stood for almost 30 years and there is still a majority of people who do not believe it is ethical to have an abortion under the current guidelines set by NY State. The majority of people do agree that it is okay to have an early abortion in the first trimester. So if abortions are legal and the majority of people think it is okay to have an early abortion, is it ethical to use stem cells for the purpose of striving to cure diseases? Just answering these two questions does not give us the answer to whether or not it is ethical to use stem cells. Unfortunately the only way to obtain information on how certain diseases are acquired and how some people are more susceptible to them is by studying stem cells. With these findings we may one day have cures for some of these devastating diseases. These findings could quite possibly lead to regeneration of brain tissues in people afflicted with Multiple Sclerosis, Parkinson’s Disease and Alzheimer’s. These victims remain optimistic in that one day they may have a cure or a better quality of life. With more knowledge of stem cells, we can be better prepared to make moral decisions that we feel confident about.
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Alzheimer's Disease Education and Referral (ADEAR). (2002). http://www.alzheimers.org. ADEAR: Silver Spring, MD.
American Stroke Association. (2002). http://www.strokeassociation.org. American Stroke Association: Dallas, TX.
National Institute of Health. (2000).
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CURE, Citizens United for Research in Epilepsy. (2001). http://www.CUREepilepsy.org. CURE, Citizens United for Research in Epilepsy: Chicago, IL.
The Myelin Project. (2002). http://www.myelin.org. The Myelin Project: Dunn Loring, VA.
National Institute of Neurological Disorders and Stroke. (2001). http://www.ninds.nih.gov. The National Institute of Neurological Disorders and Stroke; National Institutes of Health: Bethesda, MD.
The National Parkinson Foundation, Inc. (2001).
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Viacord. (2001).
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